The known machine of this type comprises a static cylinder provided with two lateral walls, at least one of which is provided with a central opening to accommodate the central neck or hub which projects coaxially from at least one end of the drum. The drum presents an essentially cylindrical shape and is subject to two motions; one of rotation on its own geometric axis, and the other which describes an orbit in the inside of the static cylinder. The drum is provided with angularly spaced slots which extend axially along its periphery and which serve to permit the exit of the blades or vanes which project toward the outside. The vanes converge and are articulated by means of rings, in the manner of a hinge, around a common shaft located inside the drum. The shaft remains in a position wherein its axis is parallel to but radially spaced from the geometric axis of the drum, the shaft axis being aligned with the geometric center or axis of the static cylinder. The vanes thus are radii of the static cylinder and are fitted, at their radially outer ends, with sliding devices for engagement with the internal wall of the cylinder. The axial ends of the vanes also have sliding devices for engagement with the lateral walls of the cylinder. The vanes are supported on the drum by swivel joints which permit the vanes to radially slide inside the drum and which in addition let them vary their relative angles among themselves. The swivel joints are essentially cylindrical segments which, by their flat sides, engage the vanes and by their cylindrical sides engage the axial cuts or openings of the drum. The drum itself has a cylindrical concave profile for engagement with the swivel joints so that it is possible for them to perform an oscillating circular motion relative to the drum. The drum is assembled on one or more eccentrics which act as a crank arm, said eccentrics being drivingly coupled to the motor or driving shaft which exits from the machine so that each rotation of said shaft causes the drum to perform a complete circular orbit. The drum is rigidly fitted, on the central coaxial hub thereof, with a cylindrical pinion which, as it moves through its orbit, meshingly engages the internal teeth of a ring gear located in the same radial plane as the pinion. The ring gear is static and it is concentrically affixed relative to the cylinder so that it imparts to the drum, by its engaging the pinion, a motion of rotation about the drum's own geometric axis in a direction which is opposite its orbiting motion and therefore opposite the rotation of the motor shaft. The pinion and ring gear have a 3 to 1 engaging relationship so that for each three rotations executed by the motor or drive shaft, the drum will perform one rotation in the opposite direction.
With respect to these known motors, pumps and compressors which provide twelve complete cycles per rotation of the rotor, and specifically those machines fitted with only three vanes, reference is made to the hereinafter cited patents which are thought to be the most representative: Spanish Pat. No. 432,981; Spanish Pat. No. 432,982.
Although they relate to internal combustion engines which perform six cycles for each rotation of the rotor, the following patents are also cited since the new developments of this invention are compared thereto in the following description: French Pat. No. 2,201,715; U.S. Pat. No. 4,314,533.
In the class of engines, compressors and pumps described above, when there is formed a minimum chamber, as defined by one of the sectors of the drum between two vanes and the inside wall of the cylinder, said minimum chamber still has an appreciable residual volume since the drum rotates on its own axis at the same time as it orbits in a circular manner around the geometric axis of the static cylinder. But, in order for the drum to be able to rotate without sticking or binding against the cylinder, it is indispensible that the distance from any point on the periphery of the drum to its center of rotation be, as a maximum, the magnitude of the radius of the static cylinder less the magnitude of the radius of the eccentric or crank. If the vanes are fitted with cylindrical ring sectors on their heads, it is also necessary to deduct from the radius of the cylinder the thickness of these ring sectors.
As a consequence of the structure as explained above, the chambers as defined by the difference between the volume of the static cylinder and that of the drum with its elements, will be of minimum volume when the drum is cylindrical in shape which, as stated above, will have its radius equal to the static cylinder radius minus the value of the eccentricity. Since the radius of the drum is smaller than the radius of the static cylinder, in order to make the minimum chamber as small as possible, it is necessary to place the drum as close as possible to the internal wall of the cylinder until the cylinder wall is tangent to the middle point of the arc of the drum located between two vanes. As the radius of the drum is less than that of the cylinder, there thus remains on opposite sides of that tangency point two residual chambers which are limited by the vanes.
One of the important objects of the present invention is that of eliminating these two residual chambers which have been described above, by means of a system of mechanisms particular to this invention, as described below.
In order to examine and better clarify the basic concept of these new mechanisms, which appreciably change the energy efficiency in the mechanical transformation of these known machines, there shall be briefly explained the negative effect of these two residual chambers.
First of all there will be explained, for the sake of a comparative example, what takes place in a pneumatic or external fluid pressure engine which possesses these residual chambers. There is indicated, as one of the representative engines of that type, the one described in Spanish Pat. No. 432,982.
In such engines, when a decreasing chamber completes its discharge phase and the intake port or valve opens, at this time the chamber presents its minimum volume, but there nevertheless necessarily remains the volume of the two above-described residual chambers. If at this time a small volume of gas under a given pressure enters the chamber, the gas will expand into the volume which exists in these residual chambers, and therefore the gas pressure will decrease in the same proportion. If the volume of gas entering the chamber is the same as the volume already existing in the residual chambers, the effective pressure of the gas on the rotor system, which is what produces the motor couple or torque, will decrease by about one half, and that decrease takes place in a proportional manner during the entire intake phase, which phase is when the motoring or driving occurs.
On the other hand, if we compare the above behavior with that of an engine which does not have residual chambers, or wherein the residual chamber volume is close to zero, then when the same small volume of gas enters the chamber under the same given pressure, the initial pressure will not significantly decrease so that this pressure will be effective on the walls of the piston and vanes, whereupon the motor couple or torque is appreciably increased and the consumption of fluid is decreased, thus representing an important energy saving.
In a similar manner there will be compared a compressor of the type in which residual chambers do exist, and there is indicated, as representative of compressors of this type, the one of Spanish Pat. No. 432,981.
In such compressors, when there is effected in the chamber the compression and expulsion of the gas, the chamber is at its minimum volume, but the aforementioned residual chambers still exist, and as a result, the gas found in them will be compressed under practically the same pressure as that of the service to which the compressor is connected. The quantity of gas existing in the residual chambers will be that of their real volume multiplied by the pressure, without taking into account the expansion produced by the heat of compression. This residual gas was compressed during the compression phase, producing heat and consuming energy needlessly because this residual gas can not be expulsed due to the service pressure equilibrium. When the intake phase begins, those two residual chambers increase in volume, becoming a single common chamber, and the compressed gas which exists in them will expand, decreasing its pressure until the pressure becomes somewhat lower than that of the suction intake, at which time the compressor begins to suck in gas. For this reason, a part of the intake run is unprofitable, and this lowers the volumetric efficiency.
If these residual chambers could be eliminated upon reaching the end of the compression and expulsion run, which is an important object of the present invention, then substantially all of the gas which has been sucked in will be expulsed. Hence, when the intake run begins and the volume of said chamber increases, there will immediately occur a strong vacuum and the gases will enter from the beginning of the suction run, thus improving the volumetric and energetic efficiency.
Thus, an important object of the present invention is to provide a machine wherein, during each 90.degree. rotation of the drum and vanes, each one of the three variable chambers will have both a maximum volume and a minimum volume which approaches zero. That is, during each complete rotation of the drum with its vanes, there is formed twelve times a maximum chamber and twelve times a minimum chamber, the volume of which will be approximately zero. The positions of these zero-volume chambers with respect to the stator are angularly spaced apart by 90.degree. and always occur at the same location.
In order to obtain such a result, the axis of rotation of the drum must describe a hypocycloid in the form of a four-point star, as represented by 46 in FIG. 18, and the mechanism to obtain it is explained below.
In the above-given description of the known type of machine, it has been indicated that the drum has one or more coaxial hubs with a coaxial pinion which meshingly engages the inside of a ring gear. The pinion, in order for it to engage in a continuous manner with the inside of the ring gear in a rotating ratio of 3 to 1, a ratio which is necessary in order for the machine to execute the desired cycles, must have a diameter equal to six times the radius of the eccentricity, and the ring gear must have a diameter equal to eight times the radius of the same eccentricity. From the above it results that the ratio between the diameters of the ring and pinion is 4 to 3.
One variation of that type of engagement with the same 3 to 1 ratio is the one which exists in the internal combustion engine found in U.S. Pat. No. 4,314,533. In this latter engine, the center of rotation of the drum describes an orbit which is a perfect ellipse, but the diameter of the pinion which is coaxial with the drum is six times the value of the first eccentricity, more or less the value of the second eccentricity, which is exactly six times the value of the radius of the first eccentricity. The inner toothed ring of that engine, however, can not be circular since the geometric center of the drum describes an ellipse, and in order to the coaxial pinion to engage in a noninterrupted manner with the inside of the ring, the latter must copy the orbit of the former and it therefore has an elliptical profile but, in order to obtain the desired ratio of 3 to 1, the perimeter of the ring must be equal to 4 to 3 the perimeter of the pinion, which is a constant in all of the described machines. The engaging of a circular pinion with a ring which is elliptical in shape is feasible because the curve of the concavity of the ring is more open than the cylindrical curve of the pinion and envelops the latter with excess, something which permits the engaging. Nevertheless, in this system of elliptical engaging, there can be obtained only two positions in which, when each one of the three chambers passes by, the chambers have a volume approaching zero. Those positions are diametrically opposite by 180.degree. so that, at the most, only six complete identical cycles are possible during each rotation of the drum.
In order for a machine of the stated class to execute 12 cycles per drum rotation with a zero chamber, the geometric axis of the drum must of necessity describe a hypocycloid orbit in the form of a four-point star. This trajectory is necessary in order to obtain four positions in which, when each chamber passes one of these positions, each one of the three chambers will have a volume which is practically null. The ring gear necessary in order to obtain this trajectory would also have to possess a hypocycloid profile in the form of a star with four points, and would have to maintain with the coaxial pinion of the drum the essential 3 to 1 ratio. If the ring gear possesses the shape of a four-point hypocycloid, then when the pinion which engages the inside of the ring gear within any of its quadrants comes to a position near one of the ring points, the teeth of the pinion also meet the teeth of the adjacent quadrant of the ring gear and thus it is impossible for them to properly engage. In addition, when those teeth of the pinion meet in the adjacent quadrant of the ring gear, the relative engaging between them is the reverse, that is to say in the opposite direction, and therefore making it impossible for the system to operate.
If the above-described engaging of the pinion and ring gear could be achieved without teeth, in a manner which would be a perfect threadlike engagement without slipping, the fluctuation in the rotation of the drum with its consequent accelerations and decelerations would render its proper functioning practically impossible. All of this assumes that such a type of threadlike engagement would be possible to construct.
Up to this point, there has been set forth a schematic description of the existing machines of this general type, and there have been cited those patents which are considered as most representative, in order to better explain and situate the innovations and mechanisms which are the objects of the present invention, and which will be described below.
In order to achieve the rotation of the drum so as to follow an orbit in the form of a four-point star, the conventional pinion and ring gear as mentioned above have been replaced by driving forks and a driven triangle, which constitute one of the preferred mechanisms of the present invention, in order to obtain, in this type of machine, the mentioned chambers with an approximately null volume.
The aforementioned mechanism basically comprises an equilateral triangle in the vertices of which there are located three parallel knobs or pins which are directed in the same direction so as to be parallel to the axis of rotation. The triangle is mounted on and against the drum in a manner very similar to, and substitutes for, the coaxial pinion which exists in the above-described known machines. The rotation of the triangle is controlled by driving forks which cause it to rotate with the same 3 to 1 ratio necessary for the production of the twelve work cycles in an engine with three vanes, and which are capable of additionally controlling the drum by accelerating or decelerating it at those times when accelerations and decelerations are needed to provide good operation and efficiency. The driving forks can also impart to the drum a completely uniform velocity, it being understood that the output shaft of the machine also rotates at uniform speed.
Another object of the present invention is that of obtaining a machine wherein the center of rotation of the drum describes a hypocycloid in the form of a four-point star so that, when the three chambers pass through each of the four quadrants, each chamber will have an approximately nonappreciable volume, the advantages of which in volumetric as well as energetic efficiency have already been presented in the aforementioned comparative descriptions.
Another facet of the invention is that it makes it possible to balance the drum together with its complements, by means of a mechanism which obtains the transformation of the four-point hypocycloid, permanently adjusted by its center of masses or of gravity in a circle, thus cancelling the components which might result from its accelerations and decelerations and balancing that resultant in a conventional manner by means of counterweights of circular rotation.
In order to clarify the most important concepts which characterize this invention and substantially modify the known types of machines, there are attached to the present description illustrative drawings, given only as an example, in which there are indicated the most essential particularities of the invention.